Lawrence Livermore National Laboratory (LLNL) researchers have 3-D printed live cells that convert glucose to ethanol and carbon dioxide gas (CO2), a substance that resembles beer, demonstrating a technology that can lead to high biocatalytic efficiency.

Bioprinting living mammalian cells into complex 3-D scaffolds has been widely studied and demonstrated for applications ranging from tissue regeneration to drug discovery to clinical implementation. In addition to mammalian cells, there is a growing interest in printing functional microbes as biocatalysts.

Microbes are extensively used in industry to convert carbon sources into valuable end-product chemicals that have applications in the food industry, biofuel production, waste treatment and bioremediation. Using live microbes instead of inorganic catalysts has advantages of mild reaction conditions, self-regeneration, low cost and catalytic speci?city.

In a case study, the team printed freeze-dried live biocatalytic yeast cells (Saccharomyces cerevisiae) into porous 3-D structures. The unique engineered geometries allowed the cells to convert glucose to ethanol and CO2 very efficiently and similar to how yeast on its own can be used to make beer. Enabled by this new bio-ink material, the printed structures are self-supporting, with high resolution, tunable cell densities, large scale, high catalytic activity and long-term viability. More importantly, if genetically modified yeast cells are used, high-valuable pharmaceuticals, chemicals, food and biofuels can be produced as well.